JPH0674850B2 - Metal diaphragm valve - Google Patents

Description

Detailed Description of the Invention

[Industrial applications]

The present invention relates to a diaphragm valve using a metal diaphragm having a relatively small diameter used in various gas industries, analysis, medical care, biotechnology, instrumentation and the like.

[Prior art]

Conventionally, as a valve using a metal diaphragm, for example,
There is one disclosed in JP-A-61-244976 as shown in the figure. This is a case 10 in which a stopper seat 15 is provided on the bottom surface of a shallow recessed stopper chamber 16 that communicates with a fluid inlet 11 and a fluid outlet 12, and a stopper chamber 16 that is disposed above the stopper seat 15 Ni-Ti that keeps airtightness and blocks fluid by contacting the stopper seat 15 by pseudo elastic deformation
It consists of an alloy diaphragm 17 and a spindle 18 which is arranged above the diaphragm 17 so as to be able to move up and down and rests against the valve seat 15, and is opened by the restoring force due to the pseudo-elastic characteristics of the Ni-Ti alloy diaphragm 17. Sometimes diaphragm 17
The fluid cutoff opener is characterized in that the valve is separated from the stopper seat 15. That is, the diaphragm 17 is formed by using a Ni-Ti based alloy and undergoes pseudoelastic deformation at a temperature exceeding the set Af transformation temperature. Then, it was used at a temperature condition slightly higher than the Af transformation temperature, and the spindle 18 was pressed downward to press the diaphragm 17 against the stopper seat 15 against the pseudo elastic deformation of the diaphragm 17 and bulged downward due to the pseudo elastic characteristic. Transform into a state and plug
Close to 15 at present. When opening, when the spindle 18 is pulled upward, the hollow portion of the diaphragm 17 is contracted by the spindle 18 of the diaphragm 17 due to the pseudo-elastic property of the Ni-Ti alloy and restored to a flat plate shape. is there. The diaphragm 17 is sandwiched between the housing 10 and the presser foot 23 by a cap nut 21 that is fastened to the housing 10 via a gasket 22, and holds the stopper chamber 16 in an airtight manner.

[Problems to be Solved by the Invention]

The drawbacks of the fluid cutoff opener are as follows. B) Gasket to keep airtightness of the diaphragm clamping part
22 is used. Therefore, when a corrosive gas is used as the fluid, the gasket is corroded and deteriorated. Further, in the field of analytical medicine and the like where cleanliness is required, foreign matter generated from the gasket may be mixed in the fluid. (B) A Ni-Ti-based shape memory alloy must be used as the diaphragm 17, and it is difficult and expensive to control the Af transformation temperature of this alloy. C) The valve can be used only under certain conditions because the temperature during use changes depending on the installation location and fluid temperature. D) Since the diaphragm 17 is a deformation that gives a tensile force directly within the pseudo-elastic deformation in a state where the outer periphery is clamped and fixed,
A large amount of deformation cannot be obtained, only a small lift that opens the valve seat can be obtained, and the flow resistance through which the fluid passes becomes large. E) When the valve is closed, the spindle 18 is forcibly deformed against the original restored shape, so the pseudo-elastic properties of the shape memory alloy are gradually lost due to repeated use over a long period of time, and the restoring action is restored. Will not work. The present invention provides a diaphragm valve and a diaphragm for a diaphragm valve that solve the above problems.

[Means for Solving the Problems]

The gist of the present invention is to dispose a load means for displacing a central portion of the diaphragm in a valve seat direction with respect to the diaphragm, the outer peripheral portion of the diaphragm being hermetically sandwiched between the valve and the valve seat. A diaphragm valve provided on the side opposite to the seat, in which the diaphragm is brought into contact with the valve seat by applying the load means, and the diaphragm is self-returned to its original shape by releasing the load means to open and close the valve, wherein the diaphragm is at the center. The part bulges into a partial spherical shell shape with a large radius of curvature in the direction away from the valve seat, and consists of a metal thin plate plated with a metal softer than the material of the diaphragm at least in the peripheral part, and the load-displacement characteristic of the diaphragm is a maximum value. And a minimum value, and the minimum value is a positive load.

[Action]

Since the present invention has the above-described configuration, among the diaphragms that elastically self-repeatly restore, particularly the load of the diaphragm-
The displacement characteristic has the property of having a maximum value and a minimum value,
That is, the diaphragm valve is not proportional to the load-displacement characteristic and has a large displacement with respect to the load, and has a property of drawing a maximum value and a minimum value. Therefore, the displacement amount can be increased with respect to the load as compared with the case where the load and the displacement are proportionally increased, and since the minimum value is a positive value, elastic self-repetitive restoration is performed. Therefore, even in a diaphragm valve having a self-restoring force, the load-displacement characteristic does not change proportionally, so that a diaphragm having a large opening / closing lift in which only the amount of displacement greatly changes can be obtained. Further, it is not necessary to separately provide a member for restoring the valve, and the valve can be opened and closed simply by displacing the central portion of the diaphragm toward the valve seat side on the side opposite to the valve seat. Further, the diaphragm clamping portion is sealed by the soft metal plated on at least the peripheral portion of the diaphragm. Therefore, since it is not necessary to provide a sealing material such as synthetic resin inside the valve, there is no risk of foreign matter entering or deterioration of sealing performance. As a result, it is possible to obtain a clean diaphragm valve having a simple shape, a large flow rate and no generation of metal powder.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. Reference numeral 1 is a main body of the diaphragm valve, which is configured as follows. An inflow port 3 is formed on the left side, an outflow port 4 is formed on the right side, an upward flow path 5 that is connected to the inflow port and faces upward in the flow direction is formed in the central portion, and an outflow port 4 is formed on the outflow side of the upward flow path 5. A downward flow path 6 is formed which is connected and whose flow direction is downward. A valve seat 7 is provided at the upper end of the upward flow path 5, and the upper surface of the valve seat 7 is plated with a soft metal such as Al, Cu, Ag, and Au. The upper part of the valve body is open and the lid 2 of the body 1
The main body 1 as a stopper for the fitted lid
A step (12) is formed at the fitting portion of. By fitting and mounting the lid 2 on the main body 1, a fluid chamber 13 is formed between the upper portion of the main body 1 and the lid 2, and the fluid chamber 13 connects the upward flow path 5 and the downward flow path 6 to each other. . When the main body 1 and the lid 2 are fitted and mounted, a diaphragm 9 made of a thin stainless plate is provided on the upper surface of the upward flow path 5 of the main body 1, and the outer peripheral portion of the diaphragm portion 12 and the lower surface of the outer peripheral portion of the lid 2 are provided. Hold it in a sealed manner with. This clamping is performed by cutting a screw on the outer peripheral portion of the upper part of the main body and screwing and tightening a lid holding nut 10 that is screwed onto this male screw. The diaphragm 9 is formed by stacking 1 to 10 stainless steel thin plates, and the diaphragm 9 made of Al, Cu, Ag, Au, etc. is formed on the lower surface of the bottom of the stack of the above stainless steel thin plates.
The metal, which is softer than the above material, is electroplated to a thickness of 5 to 10μ. This plating may be applied to the lower surface of the lowermost step and the upper surface of the uppermost step, or may be applied to at least the outer peripheral upper and lower surfaces of each stainless steel diaphragm. The central portion of the diaphragm is in the shape of a partial spherical shell having a large radius of curvature which is inflated to the upper side. The lid 2 has a through hole through which the valve rod 8 penetrates, and the lid 2 and the valve rod 8 are screw-joined and screwed to each other at this through-hole. A handle 11 is detachably fixed to the upper portion of the valve rod 8, and the valve rod 8 moves up and down by rotating the handle 11. The lowermost end surface of the valve rod 8 is in surface contact with the upper surface of the diaphragm 9, and the handle 11 fixed to the valve rod 8 is rotated to lower the valve rod 8 to push down the diaphragm 9 at the same time. The diaphragm pushed down is finally in the upward flow path 5
The valve is fully closed by pressing the valve seat 7 attached to the upper part of the valve. After that, when the valve rod 8 is raised by rotating the handle, the diaphragm 9 follows the valve rod 8 and rises. That is, the diaphragm 9 opens the flow port due to the elastic force of the diaphragm 9. When the diaphragm 9 is pushed down by the valve rod 8 to a fully closed state and then the valve rod 8 is raised to raise the diaphragm 9 to open the valve, the shape of the diaphragm 9 that the diaphragm 9 follows the valve rod will be explained. This will be described with reference to FIGS. 2 to 4. FIG. 2 is a vertical sectional view showing the shape of the diaphragm 9 of this embodiment, which is a partial spherical shell shape having a large curvature. In FIG. 2, the radius of curvature of the diaphragm is R, the plate thickness of the diaphragm is t, and the angle formed by the straight line connecting the center of curvature of the diaphragm and both ends of the spherical shell end of the diaphragm is 2β. Next, as shown in FIG. 3, when the diaphragm 9 is pushed by the valve rod 8 with a load of PKg, the displacement of the diaphragm is δm.
Let m. Load P, diaphragm thickness tmm and angle βrad
The relationship between P and δ when the value of α represented by is variously changed (when α is used as a parameter) is as shown in FIG. Here, α is R · β ² / t, the plate thickness t of the diaphragm 9 is a stainless steel thin plate sufficiently smaller than the radius of curvature R of the diaphragm, and a plurality of these thin plates are superposed. The curves in FIG. 4 are as follows: α = 2.1, α = 5.37,
The displacement amount δmm of these diaphragms 9 when the load PKg is applied to the three kinds of diaphragms 9 with α = 6.27 is shown, and the curve in the figure shows the state deformed below the position connecting the outer peripheral clamps of the diaphragms. ing. In the figure, the displacement amounts δ when a load of 5 kg is applied to each of the three types of diaphragms α = 2.1, α = 5.37, and α = 6.27 are δ1, δ2, and δ3, respectively. Here, when the displacement amount δ of the diaphragm 9 is large, this diaphragm 9 indicates that the maximum displacement amount that can be displaced following the valve rod 8 is large, and δ2 and δ3 have a lift more than twice that of δ1. If this maximum displacement amount δ is large, it means that the flow rate in the fully opened state of the valve can be large and the flow resistance can be small. In the figure, the diaphragm 9 with α = 2.1 shows a proportional relationship in which the displacement amount δ increases as the load P increases over the entire displacement amount. On the other hand, α = 5.37 and α == 6.
The 27 diaphragm 9 has a displacement amount δ that increases as the load P increases up to the point A where the displacement amount δ is 0.2 mm, but the displacement P is smaller than the load at the point A from the point A to the point B. The displacement amount δ increases. Here, the displacement amount δ of the diaphragm 9 with δ = 6.27 is from C to D.
The load P is negative in the region of. This means that the load P is applied to the diaphragm 9 with α = 6.27, and the displacement amount δ of this diaphragm 9 is increased, so that the load P is 0.
When the point C is reached, the displacement amount increases up to the point D without applying the load P thereafter. Therefore, after the point C is exceeded, even if the load P is released, the displacement amount δ of the diaphragm 9 does not return to the original 0 point. That is, even when the diaphragm 9 is pushed down by the valve rod 8 when the valve is opened and closed and the valve rod 8 is then raised, the diaphragm 9 does not follow the valve rod 9 and the valve function is lost. Particularly in the present invention, the fact that the load-displacement characteristic of the diaphragm does not have a negative region is a fundamental problem related to valve opening and closing. When the load-displacement curve of the diaphragm 9 is within the positive region, It is called the elastic deformation zone. Therefore, when selecting the shape of the diaphragm 9, care must be taken so that the deformation amount δ can be large and the load P does not have a negative region. Further, the positional relationship between the outer peripheral portion clamping position of the diaphragm 9 and the valve seat 7 must also be set so as to be deformed within the elastic region of the diaphragm in consideration of the displacement amount δ. From the above description, the diaphragm 9 is suitable as a valve when α is smaller than around 5.37 and the displacement amount δ is large because the valve lift is large and the flow resistance of the valve is small. Therefore, in the present invention, the diaphragm is used in which the load-displacement characteristic of the diaphragm 9 has a maximum value and a minimum value, and the minimum value is a positive load. Here, if α = 5.4, then α = R · β ² /t=5.4. Let φK be the diameter of the sandwiching part that sandwiches the outer periphery of the diaphragm 9 in FIG.
Since sinβ = K, R = K / 2 · sinβ, and α = R · β ² / t = (K / 2sinβ ² ) · (β ² /t)=5.4, so (K / 2t)・ (Β ^{2 /} sin β) = 5.4. From this equation, β is determined when the diameter φK of the diaphragm clamping portion and the plate thickness t of the diaphragm 9 are determined, and when φK and t are determined, the radius of curvature R of the diaphragm 9 that follows the valve rod 8 is determined.
You can decide. Although the valve rod 8 is driven by the rotation of the handle 11 in this embodiment, it may be driven by pneumatic pressure or magnetic force. In the metal diaphragm valve according to this embodiment, the sandwiching portion of the diaphragm is sealed by the soft metal plating applied to the peripheral portion of the diaphragm. Further, the metal diaphragm and the metal valve seat surface seal and open / close. Therefore, there is no component other than metal such as synthetic resin inside the valve, and there is no risk of foreign matter entering the fluid or deterioration of the sealing performance. Further, since the diaphragm has a large displacement amount among the diaphragms having the property of self-elastic return, it is possible to obtain a diaphragm valve having a large opening and closing lift capable of opening and closing following the valve rod, a large flow rate, and a small flow resistance. . Further, since it is not necessary to provide a spring or the like for returning the diaphragm, there is little dead space, and a clean valve without friction metal powder is obtained.

【The invention's effect】

The diaphragm valve of the present invention is a diaphragm capable of taking a large amount of displacement among the diaphragms having the property of self-elastically returning. Therefore, it is possible to obtain a diaphragm valve having a large opening / closing lift capable of opening and closing following the valve rod, a large flow rate, and a small flow resistance. Further, the metal plating applied to the diaphragm seals the sandwiched portion of the diaphragm. Therefore, there are no parts other than metal such as synthetic resin inside the valve,
There is no risk of foreign matter entering the fluid or deterioration of the sealing performance. Also, since there is no need to provide a spring for returning the diaphragm, there is little dead space,
A clean valve that does not generate friction metal powder can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention when a valve is opened, FIG. 2 is a vertical sectional view of a diaphragm, and FIG. 3 is a vertical sectional view when a diaphragm is pushed down by a valve rod. The figure shows the relationship between the load applied to the diaphragm and the amount of displacement, and FIG. 5 is a vertical cross-sectional view of a conventional diaphragm valve.

[Explanation of symbols]

 1 ... Main body, 2 ... Lid, 5 ... Upward flow passage, 8 ... Valve rod, 9 ... Diaphragm, P ... Load, δ ... Displacement

Claims (1)

[Claims] Claim: What is claimed is: 1. A load seat, which is disposed to face the valve seat of the valve by hermetically sandwiching the outer periphery of the diaphragm with the valve, and which displaces the central part of the diaphragm in the valve seat direction with respect to the valve seat. A diaphragm valve which is provided on the opposite side to the valve seat by applying load means to the valve seat and causes the diaphragm to return to its original shape by releasing the load means to open and close the valve. Is a partial spherical shell shape with a large radius of curvature in the direction away from the valve seat, and consists of a metal thin plate plated with a metal softer than the material of the diaphragm at least in the peripheral part, and the load-displacement characteristics of the diaphragm are maximum and minimum. And a minimum value is a positive load, a metal diaphragm valve.